thunder run n. a high-speed military convoy using offensive tactics and heavy weaponry to reach a destination; generally, a route or trip involving extreme effort or danger. Editorial Note: This term dates from at least as early as the Vietnam War. Etymological Note: The etymological information in the 2001 citation is unverified. There is a theatrical device also called a thunder run, a trough down which cannonballs are rolled in order to simulate the sound of thunder. (source: Double-Tongued Dictionary)